hens missing feathers...?

[fishmanwill]

We have a couple of hens that are missing feathers like the one pictured, at the base of their tails on their backs. What is going on? Is it molting, bugs, mating, getting picked on? We have one rooster and 14 large hens. I just want to make sure it is not the start of a problem. Thanks,

 

[Ol Grey Mare]

Do you have a rooster (or roosters) in your flock? That looks like classic rooster damage pattern.